Cramping My Style

Cramping, or more specifically, exercise-associated muscle cramping (EAMC), is as much a part of the ultra experience as GU and handhelds. Yet, it is remarkable how little The Communities – both the scientific and ultra – truly know about cramping.

I wish I’d known more. I thought I did. But sometimes knowing what we do not know is nearly as good.

In order to clear the air, and clean the slate, I’d like to review some old concepts, introduce some new ones and try to put forth practical, evidence-based troubleshooting plan if and when cramps threaten to derail your ultra experience.

The Origins of the Cramp & Salt Myth

It’s funny how often a small, inconsequential event can snowball into dogmatic law.

If you were to poll a hundred ultramarathon runners, the vast majority of respondents would claim that muscle cramps were due to “an electrolyte imbalance” or a deficiency in sodium, potassium, or other elements. The belief pervades beyond the trails: I can only smile and nod politely when my patients tell me they combat their night cramps by “eating more bananas,” implying that a potassium deficit somehow causes their cramps.

It does not.

We don’t know much about EAMC, but what we do know, definitively, is this: There is no association between blood (or sweat, or urine) sodium concentrations – or hydration status – and muscle cramps.

None. Zero.

Tim Noakes, MD, devoted 429 pages in his 2012 work, Waterlogged, to the effort of disposing that myth. I, too, did my part, with a good ten-thousand words in this column a year ago. Yet, the presence of S!Caps, Salt Stick, table salt and other supplements in ultrarunner’s pockets hasn’t diminished in the slightest.

Why? There several reasons, beginning with a miniscule but impactful study nearly a hundred years ago. Then, it was the Gatorade revolution. On top of that, mounds of anecdotal evidence: runners implicitly know that salt helps.

And you know what? It does work. We know that, with scientific evidence to boot. But why it helps is not why you think.

Exercise-Associated Muscle Cramping – What We Know

In Waterlogged, Noakes provides historic context to our belief of a salt and cramping association.

The belief in the association between cramping and sodium deficit came from a study nearly a hundred years ago, involving British mine workers. Mine owners and scientists were curious about the cause of muscle cramping in miners, so they conducted a study examining cramping miners and the sodium content of their body secretions: sweat and urine. Based on this single study, the belief that cramps were caused by low sodium was born. And, in the 1960s, scientists jumped on this nugget and ran with it.

The study was tragically flawed: insufficient subjects, a lack of controls, and – most outrageously – completely failed to show any correlation between cramping and sodium. Instead, they found a single subject with low sodium in his urine. That’s it. Thus, our belief of salt and cramping originated from a urine sodium sample of a single study, of a single miner… who did not even experience muscle cramping!

This finding lay dormant, until the 1960s. The history of Gatorade and performance is well-documented in Waterlogged, and described in detail in last August’s column. Because of several confounding factors (ad libitum hydration, sugar intake, and placebo effect, to name a few), the belief that salt benefits performance ran roughshod through the athletic community.

Today, that belief is nearly unshakable.

However, since then, all subsequent studies of sodium concentrations – in blood, muscle tissue, and urine – failed to show any association between cramping and sodium levels.

Noakes reviews the literature, and outlines the current research:

There is not a single study that shows blood electrolyte concentrations – including sodium – are abnormal at times of muscle cramping. On the contrary, four recent studies (1984-2009) have shown that cramping athletes have completely normal blood sodium levels.

There is not a single study that demonstrates dehydration to be a factor in cramping: in fact, the same aforementioned studies noted that cramping athletes are no more dehydrated than controls.

There is no evidence that body temperature of exercising athletes has any effect – that cramping athletes have higher core temperatures – on cramping during endurance activities. In fact, studies on swimmers demonstrate cramping can occur in extreme cold water conditions.

One body of studies that did find that “salty sweaters” experienced more cramps (Bergerson, 1996, 2003; Stofan, Zachwieja et al 2005), but these studies failed to have adequate control groups, and they failed to measure blood or sweat sodium concentrations at the time of cramping. Interestingly, one particular finding from these studies found that crampers had higher dietary sodium intakes, and that they sweated higher concentrations of sodium – opposite of the author’s conclusions.

When cramping occurs in people with medical conditions (such as hyponatremia), the cramps are generalized throughout the body, affecting multiple groups. In contrast, exercise-induced cramping invariably affects only specific groups involved in repetitive contractions. Therefore, it is unclear as to how a general body or blood sodium deficiency could cause cramping localized only to specific groups.

So, we may not know exactly what causes cramping, but we know what does not cause cramping: low blood or muscle sodium content does not affect cramping.

There is evidence that salt helps us in racing. But it’s not why you think. Hang in there.

What We Think We Know: Cramping & the Altered Neuromuscular Control Theory

Noakes and his colleague, Dr Martin Schwellnus (1997) have proposed another theory to explain EAMC, where a reflex – found somewhere in the muscle or nervous system – that normally balance muscle contractions, fatigues. Because of that fatigue, the exercising muscle becomes too excited and begins to cramp.

[Dr. Martin] Schwellnus developed the theory that there are reflexes in the muscle that prevent them from cramping…. When we run, and, in particular, when we run slightly faster than we want to (or that we really should be running), it seems that that reflex gets tired, and the inhibitory reflexes become less strong. And as a consequence, the excitatory impulses… become dominant. And as a consequence, the muscle goes into cramp.

And we know that, because if we look at the electrical activity in the muscles, we notice that before they cramp, the activity starts to rise. So something’s changing in the muscle, that’s making it more prone to going into cramp. And then, you continue for a bit further, and it goes into a full cramp.

And the point is, it is an electrical phenomenon, a reflex, that may originate in the brain (or more likely originates in the spinal cord), but has almost certainly got nothing to do with dehydration or sodium balance, and has almost everything to do with genetic predisposition and also has got everything to do with how tired you are, and how hard you’ve exercised.

Noakes adds,

The remedy, unfortunately, is to do lots of stretching to the [affected] muscle, lengthening the muscle, because what we have also found, is that, muscles that haven’t been lengthened – muscles that have been working in a small arc, and working in a shortened position – those are the muscles that are going to cramp. So you need to stretch the muscle, lengthen it, to make it less susceptible to cramping.

Several studies have helped to confirm this nerve-plus-muscle mechanism for cramping. (Norris, Gasteiger et al. 1957; Minetto, Botter, et al. 2008; Stone, Edwards et al. 2003) In these studies, cramps were induced by stimulating certain muscles, and cramps were abated by stimulating other muscles – reinforcing the notion of a balance between motor firing occurs in a non-cramped state, and that this is disrupted with prolonged, fatiguing activity.

Who Cramps & Why

More recent work has studied the incidence and prevalence of cramping. (Schwellnus, Drew et al. 2011) Once again, these studies found that no difference in hydration or blood sodium concentrations between crampers and non-crampers.

However, two factors did emerge that separated crampers from non-crampers: the crampers ran faster (e.g., they were among the fastest, most competitive athletes) versus the rest of the field, and they had a history of cramping in previous efforts.

This is insightful: you cramp when you run hard, and when you have “the habit.” Since both exercise intensity and previous experience are central nervous systems, these findings support the neuromuscular control theory of cramping.

Salt Intake & Performance: The Pickle Juice Study

Athletes have known for a long time that salty foods and drinks decrease cramping and enhance performance. You start to cramp, so you stop at the aid station and dip that potato in salt. Or you pop the S!Cap. Then, within seconds, you feel better.

We just don’t know how or why. A recent study now sheds some light on that.

The intriguing “Pickle Juice Study” was performed in 2010 by a group of exercise scientists at North Dakota State University. The researchers exercised a group of subjects for a prolonged period of time to elicit the following effects: a water loss of 3% of body weight, a sodium loss of at least 145mmol in sweat, and onset of exercise-induced muscle cramping.

Immediately after all three conditions were met, the subjects consumed 75mL of pickle juice, while a control group drank 75mL of water (and a third group, no intake). The study found that, for both drinker groups, a reduction in cramping occurred in under 90 seconds, and the pickle juice reduced the duration of cramping 49 seconds faster, compared to a just-water group.

Because of this rapidity, the effect of the pickle juice could not have been due to changes in blood sodium or overall hydration levels, as insufficient time had elapsed for the stomach or intestines to absorb the salt or water. Moreover, a follow-up study noted that – even with sufficient absorption time – drinking 75mL of pickle juice had no effect on blood sodium (or hydration levels).

So, an effect was measured, but systemic changes were impossibly fast. What, then, caused the change?

The authors speculated that drinking the pickle juice – either through its salinity or acidity – triggered a neurological reflex, somewhere in the mouth or throat, that traveled to the brain. Therefore, it was a brain effect – not a GI or blood effect – that reduced the cramping. This study supports the neuromuscular muscle cramp theory, that the nervous system has ultimate control over cramping.

Noakes discusses this, as well, in the same podcast:

As far as sodium balance goes, we do not need to take sodium, because you will be excreting during the race any excess sodium you’d take the day before. And any excess sodium you take during the race will simply appear in your urine…. We know that, so you don’t actually need it to manage your sodium balance.

But there is a component we know, that the brain has a link to the tongue, and when you put salt on your tongue, the brain recognizes that you are putting salt into the body, and it may well modify your performance. We certainly know that if we put food in your mouth, particularly carbohydrates, but I think protein and fat, but they haven’t been studied yet… your brain immediately interprets that, ‘This is good!’, and allows you to run faster.

We know that if you’ve got a cramp, and you put a salty drink on your tongue, you will reduce the cramp, it will tend to break, within about 40 seconds. So that can’t be because of salt entering your intestine and being absorbed, it’s because the salt is acting through a reflex in the brain, and the brain is for some reason responding to the salt and saying, ‘OK, we mustn’t have muscle cramping at this time.’

Because muscle cramping is a brain/spinal cord phenomenon, and has got nothing to do with the salt balance in your body. So my point is… people may take salt, and they may say, ‘My gosh! It does improve my performance!’, and I would not discount that, but it’s not acting by improving the salt balance, it’s acting in the brain… it’s not confusing the brain, but it’s interpreting that salt is coming into the body and that is good, and therefore you can run faster.

Muscle Cramping & The Central Governor

Let’s review what we know (or think we know, or know what we don’t know) so far:

Muscle cramping is a neurological, “electrical” phenomenon, likely centered in the central nervous system, where reflexes become unbalanced, affecting the muscle.

The muscle is most susceptible to cramping with prolonged fatigue and (according to Noakes), when we “run faster than we should.”

Sodium or electrolyte balance – in the blood stream or muscle cell – has zero effect on cramping.

Sodium (and possibly water, sugar, and fat) tasting in the mouth (and possibly upper GI tract) does have a positive effect: dampening cramping and improving performance. But the rapidity of this effect suggests that it is the brain alone that creates this effect.

Muscles most affected by cramping are those repetitively used and confined to a small arc of motion.

The only known treatments to cramping are to slow down, stop, and stretch the muscle to a maximally lengthened state.

These concepts suggest that muscle cramping, therefore, might be an action of the Central Governor. Recall from last month’s column: the Central Governor protects the body from danger, and is likely the major determinant for running performance. As such, the mechanisms above suggest the brain is trying to protect the body – either the brain, heart, or muscles – from damage. And in this instance, that protective mechanism is cramping.

To add to that idea, Noakes notes that cramping might also be a protective response to chronic, micro-trauma to over-trained, over-stressed muscle tissue:

What we used to think of as muscle tears… now we’re beginning to think… it’s something to do with the fascia surrounding the muscle, that becomes irritated, and that then causes the electrical activity in the muscles to go up, and they start to cramp…. I think what we’re going to find is that injury is a part of it: if you’ve been training hard and the muscle fascia is slightly damaged in some way (that we don’t yet fully understand). Go out and race, and after a time, what happens is, the muscle starts to cramp a little bit, they’re too small for you to notice, and then all of a sudden, the whole muscle goes into cramp. But as it resolves, you find that there are these little nodules that continue to be cramping. And in my view, that is likely to be injury, rather than anything else…. It may be a protective reflex that stops you from running and damaging your muscle any more.

Put it all together: cramping, then, very well could be a self-preserving act: “This guy won’t slow down, he’s working too hard – I’m going to make him slow down.”

Based on these concepts, soothing the Central Governor is the key to treating and preventing cramps.

Based on what we know, I propose the following strategies to treat and prevent muscle cramping:

#1 – Run Sustainably

Through some mechanism – either neurological, cardiac, or neuromuscular – the brain judges your current effort and decides whether or not it is sustainable. Maintaining an unsustainable pace early in a long ultramarathon may trigger the onset of muscle cramping. Why this happens, in absence of energy deficit or other perceived physical duress, is unclear.

That said, if you have a cramping issue – make note of the paces and conditions (heat, altitude, terrain) at which cramping occurred. Adjust your pace downward, accordingly, and gauge the effect.

An even better way to gauge sustainability is to use a metric, such as heart rate. Heart rate is all-encompassing: it takes into account those variables, as well as fatigue, anxiety and stress, and tissue trauma. If heart rate is high, your system is stressed, and needs a break.

For me, I failed to make any adjustment to pace or effort at this year’s Western States 100: I continued onward with little slowing, or stopping. My cramps continued, unremittingly, and irreversibly, as a result.

Conversely, it’s worth noting two successful examples of cramp-management at last week’s Western States. Firstly, was iRunFar’s Andy Jones-Wilkins. As noted in his race report:

By the time I rolled into Robinson in 53rd place my quads and hamstrings were cramping pretty intensely, so I knew I had to top off pretty aggressively on electrolytes.

My plan from the outset was to spend a bit more time at the early aid stations to make sure I was taking care of myself and dosing my effort sufficiently to have legs from the River in. However, the eight minutes I spent at Robinson Flat were, perhaps, a bit too long…. I ate my yogurt/granola concoction, topped off my fluids, and had a double shot of “Witch’s Brew” (double strength chicken broth made with coconut water), so I ultimately didn’t get out of there until 10:45, a full 15 minutes slower than my planned split.

The question is, what decreased the cramping? Was it that barely-potable concoction of salty fluids, or scores of S!Caps? Or was it simply stopping at the aid station for nearly ten minutes – and resting the skeletal and cardiac muscle – that decreased the cramp response?

The research would suggest it was the rest, not the “Witch’s Brew,” that was successful.

Additionally, ultra veteran Scott Wolfe raced himself to an impressive 11th place male finish, noting that he took two prolonged breaks, lying in both the Middle Fork American River (mile 45) and Volcano Creek (mile 60) “until my heart rate got below a hundred” beats per minute. Was it the cooling effect that aided performance, or simply stopping and allowing his muscle tissue to rest? We don’t have a definitive answer, but again, the research suggests it was the resting of muscle tissue that was the primary benefit. However, cooling the system also provides vital positive input to a cautious, stressed-out Central Governor.

Either way, these decisions paid off in a big way for both Andy and Scott: they ran sustainably and kept the Central Governor appeased throughout the day.

#2 – Run Efficiently!

Given what Dr. Noakes stated about repetitive muscle use playing a role in cramping, it is vital that the run stride be as efficient as possible. Muscle groups such as the medial quad and calf tend to cramp because these groups bear the brunt of braking forces in an efficient stride: a foot strike too far in front of the center of mass causes excess force absorption, “braking,” to occur in these groups. An efficient foot strike will minimize stress on these groups.

Moreover, having a compact, but balance stride will also help: as Dr. Noakes notes, muscles that function in a “small arc” – or small pattern of movement – are most susceptible to cramping. Having adequate hip and knee flexion/extension provides maximal range of motion and “stretch break” for the working muscles.

Be form-focused!

#3 – Ply the Central Governor With Its Favorites

Low salt doesn’t cause cramps, but taking small portions of salt helps. Keep the Governor happy with frequent – but measured – doses of its favorite go-to food groups: water, salt, sugar, and even fat. Maintain a “see-food diet”: if it looks (and tastes) good, eat it. The Governor will be pleased, and allow for improved performance.

But don’t take this too far. The diminishing law of returns is a steep slope: over-doing water, food, and salt are dangerous, their effects ranging from general malaise (in the case of a sour or full stomach) to dire (hyponatremia).

#4 – RELAX. SMILE. LAUGH!

Cramping is a neurological phenomenon. So is pain. If cramping, like pain and other complex neurological processes, are of central origin, we, then, have more control than we realize. In discussing the physiology of pain, we noted the impact of stress, anxiety and mood on pain – and how it acts as an amplifier of electrical (and chemical) signals.

Defuse the threat. Recognize that anxiety, worry, and grief about cramping – and its impact on your performance – may increase its severity. Conversely, simply relaxing and – taking it to the extreme – going out of one’s way to smile and even laugh – may have a potently dampening effect!

I fought the blips constantly, as if tip-toeing across a mine field –one false move and it was a death of tetany, and at best a painful limp to the finish. At worst? A DNF.

Strategizing, I realized I needed total relaxation. Moreover, I had to smile. So I did. A huge, ridiculous grin, almost non-stop, was pinned on my face as I floated along down the road and onto the final climbs…. I had to soften it as to not look insane as I passed a Park Ranger in his squad, then a random aberration of [Dave Mackey] running downhill past me. “Hey Dave!”, I said, the smile slightly less ridiculous. But it worked!

Indeed, after spending hours that day, literally eatingNuun electrolyte tabs (deserving of a trip to the periodontist, post-race), what ultimately resulting in the cramps ceasing was relaxation: smiling, and – albeit forced – laughing out loud. The cramps abated and did not return for the remainder of the race, despite maintaining and ultimately increasing pace at the end.

#5 – Slow down.

Should those mid-run strategies fail to curb cramping, you must slow down. Period. Again, the science states that – outside neurological disruption – a slowing of pace – thus lowering the demand on the muscle and nervous system – is required.

Should slowing fail to stop the cramps, it is time to stop running. Walk, or stop at an aid station. Per Noakes: stretch the repetitively-shortened muscle with copious stretching. Also try icing, as much for the neurological input as for cooling. Ice is a frequent tool for health-care practitioners to use to “break” (or decrease) high muscle tone in neurological patients.

#7 – …Know When to Fold ‘Em.

Should cramps persist and muscle cramps segue into severe muscle pain, perhaps it is time to stop. This is a deeply personal decision, depending on your race goals, that point at which you are at in the race, and personal experience.

But recognize that, with severe muscle cramping, pain, and greatly reduced pace, the brain is trying to tell you something: you’ve over-done it, tissue is compromised, and you need to stop. Ultimately, it is up to you as to whether you listen to that message. If we always stopped when the brain said so, no one would ever finish an ultra. However, much severe suffering might be avoided by doing a better job of listening to the body, early and often.

* * * * *

Knowledge is power, and muscle cramping is the body telling you that something isn’t right. Listen to the body, recognize that there is a problem, and act accordingly. Few things are more rewarding than problem-solving, and over-coming obstacles, in training, racing, and life. My hope is these nuggets will help you solve your problems and “keep moving to the finish line.”

Call for Comments (from Bryon)

So, it’s probably unnecessary to make an express call for comments here, but

When have you experienced cramps in the past? Do the above stated causes likely apply?

How (do you think you) have you resolved cramps in the past?

What are your thoughts on the growing evidence for mental stimulus greatly affecting physical performance during endurance sports?

Joe Uhan is a physical therapist, coach, and ultrarunner in Eugene, Oregon. He is a Minnesota native and has been a competitive runner for over 20 years. He has a Master's Degree in Kinesiology, a Doctorate in Physical Therapy, and is a USATF Level II Certified Coach. Joe ran his first ultra at Autumn Leaves 50 Mile in October 2010, was 4th place at the 2015 USATF 100K Trail Championships (and 3rd in 2012), second at the 2014 Waldo 100K, and finished M9 at the 2012 Western States 100. Joe owns and operates Uhan Performance Physiotherapy in Eugene, Oregon, and offers online coaching and running analysis at uhanperformance.com.

There are 139 comments

So after reading your article (nicely done, by the way, very informative), and scanning several of the responses, my primary question is this: If cramping has been an issue during long race efforts, does this simply point toward the need for more training? If cramping mostly, or entirely, comes down to the Central Govenor trying to protect us from ourselves, doesn't this just mean that I have to train my body/Central Govenor to be in its happy place for longer? There's no quick fix of salt, etc, that can overcome lack of training, right? After a recent bout of cramping in calfs and quads I'm now trying to reset my training and work back up to longer distances/time on my feet but at a slower pace, trying to expand my endurance and stay happy for longer. (I'm gearing up for my first 50-miler this fall.) Am I reading you right?

I would argue that more training is valuable, but that training should likely be at the race effort and duration (or just race more, slightly off your cramp pace?) The reason I tend to come close to or achieve cramping in races (if it happens, it pops up almost on the clock at hour 4) and never in training (even up to 8 hour/50 mile solo efforts) is simply one of intensity. Thus to strengthen or toughen or whatever those muscles, more regular training might help me, but likely better would be full on race intensity for long durations up until the point of feeling cramping coming on, and then holding that just-sub-cramp pace.

Thanks KenZ. That's more or less my approach as well. I'm a novice so am trying to learn by feel as much as anything. I have to admit the concept of "race pace" versus training pace is sort of lost on me, but I understand it's an important distinction. In my limited experience I've tended to get caught up in race day excitement and took off at half marathon pace, let's say, while running a marathon, only to suffer the consequences in later miles. Now I'm trying to train for time on my feet and hopefully more speed will come with greater efficiency. Maybe now I won't ne so concerned about taking salt tabs as well. One less thing to carry!

Ah, love it!!!! I have been messing with cramps for years!!! trying to figure it out. I knew it wasn't because of being dehydrated, I knew it wasn't from lace of salt or electrolytes as I took 40 electrolyte tablets in one Ironman race and still cramped. I've cramped with and without S caps or endurolytes. I do find I get relief if I open the capsule up and dump under tongue but it is only temporary relief. My cramps will come on and build to the point I almost have to stop or do stop but I push through as they build, they peak and subside and go away as if no big deal and they never occured only to sneak back up again hour, or hours down the trail/road. Mainly my calves and my inner thigh and when climbing anterior/lateral of ankle lower leg.

I ran the WS 100 this year and I cramped withn the first 7 miles and said "uh oh, not good" but I just was careful not to point my toe. then my inner thigh went heading into Robinson Flat but I said "f!@# this" and pushed through keeping my mind positive and looking and pressing foward. My heart rate had been running >140-150 at times which I believe is above my cramping threshold. From Robinson Flat on, my heart rate was lower (I couldn't get it higher) and I never cramped again from RF to Rucky Chucky. (pulled due to cut off, quads wasted, not cramped) Had ghost cramps but no major cramps. I took a few endurolytes but I truely don't think they prevent them. I wore compression socks for the first time thinking it would help rid my muscles of waste products because I thought maybe that is why i cramped and when the waste products cleared the cramps would go away. But not sure if that could be true. Whether the socks helped who knows. Funny, I really didn't start cramping in ultras till maybe 45 yrs old. I ran WS 100 in 1980 at age 23 and didn't have one iota of a cramp. One other thing I did do leading up to WS 100 2013 was I was taking Slo – mag, 3 tablets every night. so who knows. But I like this theory, makes the most sense. Thanks!!!! anxious to hear more.

Yes they are, running or riding, one time had both inner thighs going, try riding uphill with that, yikes!!! but my pain threshold to them has increased cuz I know they peak and go away. better to keep moving. hurts just thinking about it, I know it probably isn't good to push thru as you are start playing tug a war with the muscle fibers pulling and stretching, hmmmmm could I be tearing the muscle?

Well this article is SUCh a relief! Mostly just to know I am not alone! I have been a runner for 32 yrs and never suffered cramping until recently.I am 56yrs old and recently had SEVERE calf cramps in mile 21 of a marathon. I NEVER have calf cramps in training-ever. I just did a 25K last weekend and again suffered SEVERE calf cramps about 2 miles form the finish.I was taking Nuun and water and slight nutrition.Both times had enough electrolytes and water. The 25K was in heat and humidity and hills I hadn't trained enough for.However I was beginning to think something was wrong with me! I will add when I was young,during pregnancy, I always got calf cramps at night.In those days they told you it was a calcium deficency. After taking calcium they immediatley stopped.I do take calcium daily now and only get running induced cramps. They stop immediately when I stop with no after affect.I did use the slowing down theory at the 25k and it kept them at bay for ahwile.I also am a barefoot runner and never have cramps when I barefoot run. These 2 race examples were with shoes. I am relieved to know I am not missing some magic secret to no cramping as I always feel like such a dork when it happens. Now I know I am not alone! I just want my running to be fun and SIMPLE-not scientific!

That is a great analogy in your last sentence, but I still don't think its completely fair.

At the very top of the article he said that he can only smile and nod politely when his patients tell him that they combat their cramps by consuming more salt, implying that an electrolyte deficit somehow causes their cramps. He clearly is saying here by smiling and nodding politely that they do not need to be consuming more salt. But yet turns right around later and says it does work.

I don't see it that way. He can only nod politely because he has no better answer. Scientists will only confirm what has been proven. All other theories will not be neither confirmed nor discarded. He doesn't say they shouldn't have taken salts. Only, why would he tell you to take salt if there is no proven theory saying why.

On the other hand, tricks that are experience-proven to work cannot be ignored as science probably knows not more than 15% about everything going on in our bodies, after millions of years of development…

Perhaps your issue is more with an undertone of smug arrogance than the worded content. I get what you're saying though, and agree. You can't have your cake and eat it too (though that's a stupid expression).

There is no intentional undertone or arrogance. It's just that when I studied, I was told that science is no science until there is proof or sufficient argument. I understand from the article that science cannot confirm that lack of salt is the cause of cramps, because then they would have to confirm also that UFO's exist as many people insist to have seen them. Which is NOT saying that salt will not help or UFO's cannot exist. So there is no contradiction. If the arrogance comes from saying science only knows 15%, then I would refer to something most scientists confirm: "the more we investigate, the more we learn we know nothing."

Thanks for the copy/paste. I think I am just not pinning the points down enough for you to see what I am really saying. Look at the very top again – at the very top of the article he said that he can only smile and nod politely when his patients tell him that they combat their cramps by consuming more salt. He clearly is saying here by 'smiling and nodding politely' that they do not need to be consuming more salt. But yet turns right around later and says consuming more salt does work.

Pretty simplistic, but is it possible, knowing that cramps are uncontrolled signals from the brain and those travel through the body as "electricity", that tired muscles accumulate chemicals that cause "shortcircuit" like a cellphone could do to flight instruments, and that salt helps to "ground" the uncontrolled electric activity…? Maybe stupid, just an idea.

This is the first piece of writing or information that I have found or heard about that makes any sense as to why I might be cramping.
I am a soccer player at a university level, not a marathon runner or anything, my calfs, hurt within 5 minutes of starting a game. It's hard to get playing time when you can barely run because you are in pain. I am going into my fifth and final year of playing at university level and all I want is to feel good when I play.
The pain started at the beginning of my second year playing at the level. Before that I had played soccer for almost 5 years and had no problems. People told me stretch, so I stretch all the time, people side potassium, salt, massages and I've tried and nothing helps.
If you have something to push me in another direction for the year I'd love to hear it.

Fascinating article which chimes with what I had thought for a long time that cramping was a defensive measure to protect against more serious injury occurring. Noakes' Central Governor Theory (and which is still only a theory after all!!) would give credence to defensive measures of that type.

But to extend the discussion a bit further – what causes cramps during periods of inactivity?

I would bet that nearly all runners of any intensity of training have experienced that excruciating awakening when a calf muscle cramp propels one out of sleep, and the bed, to get some relief by staggering around the bedroom holding onto furniture!!!

Now that can't be the CG telling the body to desist from stressing that particular muscle, so what is it????

Read: http://www.sportsscientists.com/2007/11/muscle-cr… by Ross Tucker, one of Noakes's students (and along with Schwellnuss, part of a group of Capetown researchers). If you go to part 2. What kind of muscle cramps most often? you'll see part of your answer which may compel you to read the rest of the article (and the previous related posts).

I think this is the most compelling description of why cramping occurs, though it may not exactly be "actionable intelligence."

Thanks for that link – very interesting reading and I have many of Ross Tucker's papers already so I know of his work.

However the paper is about a theory on why cramping during activity occurs which is more relevant to the body of this current discussion rather than passive cramping substantially post exercise.

The very brief summary of this theory is "Fatigue causes cramps, by interfering with the normal balance of spinal reflex control – it switches on the alpha motor neuron and the muscle contracts involuntarily."

Put that in the context of this discussion and it fits perfectly – lack of salts/electrolytes does not cause cramping it's due to fatigue interfering with the normal balance of spinal reflex control!!

However it does not explain why taking salt or similar substances alleviates cramp unless the brain accepts the message that the body is getting additional sustenance to overcome the fatigue and switches off the spinal reflex control – all done sub-consciously of course!!

personally I never get cramp in training or competition only in the dead of night afterwards – hence my interest.

So Joe means that if he would do a full day of hot humid sauna sessions (sweating salt out), without physical exercise and only drinking clear water, low in minerals, he would be cramping at the end of the day?

Well I have never tried that before as I hate Saunas but I wouldn't be surprised.

What I am saying is that when I am sweating a lot, even going easy I start to cramp eventually. It is so easily reproducible, I don't even think about it anymore. But normally it only happens in longer races and such. I'm one of those guys who comes back from a 14 mile run with salt stains all over me.

I even had my own point proved to me yet again last night. Went for a super-easy 8 miler. I'm talking almost a minute-per-mile slower than normal training pace. It's extremely humid and warm up here in Boston these days and I certainly haven't been taking any salt (I normally only take it in long races).

But 5 or 6 miles into the run — I swear to God I am not making this up — I started feeling my left calf start to cramp. I almost laughed because I'd just posted on this earlier in the day. But I was sweating so much, that my socks and shoes were already soaked.

I had to be careful the remaining couple of miles but I managed to fend off the cramps. When I got home, got showered and sat down on the couch, my legs were spasming and cramping quite a bit. My right arm cramped a couple of times. So I went and took a couple of my salt-stick pills and 20 minutes later, no cramps.

It's very rare that this happens to me in a run so short. I can't remember the last time. But that's how it always works for me. Sweating a lot means cramps. In winter time, I could go for a 20 mile run very hard and wouldn't cramp one bit.

Hi Joe, your story still fits into my unscientific thundercloud theory (comment further)You seem to be very sensitive to building up electrical charges. Maybe you could run with the Compex electrodes on your muscles connected to leds and run with flashlights working from your discharges avoiding cramps at the same time…haha. Sorry for trying to make it funny. I promise I will shut up now.

I hear ya. For me, "race pace" is definitely slower than the adrenaline-fed pace that will leave you to crash later; it's the pace that (cramping aside!) will lead you to your absolute fastest finish. If For a very hilly 50k (say, 7k vert), I'm usually at l-2 hours faster in a race than in training. That is significantly faster for such a "short" distance. Why don't I train that fast? Because I love to run, but unless it's a race, I don't love to suffer THAT much!

While I have 100% bought the argument and research that electrolytes aren't at least a 1st order aid in cramping, for you I'd keep an open mind, even in light of Noake's work. In a podcast he did about a year ago when asked about electrolytes pills, he said two things: 1. The placebo effect is both real and strong 2. You're not really going to do any harm taking them, and they don't weight that much. So while you're starting out and figuring it all out, it might be prudent to carry a small baggie with you. I don't anymore, but that's through extensive trial in both training and racing. Because there are some very experienced people on this forum who tend to disagree with this concept, that information should not be dismissed out of hand.

Stressed muscle with little movement will obstruct good blood flow, causing more accumulation of whatever is in there.

Can these accumulated "chemicals" create electrical tension (remembering the potato with electrodes at school)?

Could it be that we produce this way some kind of thunderstorm cloud, building up electrical tension and that cramps are caused by the lightnings in that cloud, electrical discharges (epilepsy)? This would mean it's not the central governor sending the impulse.

It could explain why we can get the cramps at night, long after exercise (pulse and blood flow relax but accumulation of electric tension continues)

Could salt or electrolytes avoid accumulation of tension as they help the continuous exchange of electrons?

If it is an electrical problem, could it be solved with electrodes, like reversing the compex machine?

Sorry if it sounds ridiculous, but I see some logic in it and have never read an aproach this way.

A slight direction change here: am I to infer from this article that taking salt pills/electrolytes while distance running will also have no physiological effect on my hydration levels? Is not the main reason people take salt to aid in absorption of water by the stomach — purely to stay hydrated (and having nothing to do with cramping)? If I'm understanding this article correctly, I'm to believe that taking salt in addition to water for hydration purposes has no effect besides as a placebo for my brain? The fact that the (possibly excess) water sloshing in my stomach goes away within 5 or so minutes after eating the salt pill vs. significantly longer if no salt is consumed is psychological and not physiological?

Most folks I know do not take salt tabs to aid in hydration… they do it to "maintain electrolyte levels." While not at all a focus of the article, it remains a separate topic whether or not an isotonic (or other) electrolyte-laced beverage aids absorption in a clinically meaningful way.

Sorry, it wasn't my intention to get off topic, I was just really taken aback by what I was reading. I've been under the impression that the main function of sodium ingestion during strenuous (sweaty) activity is to aid in the absorption of water by the stomach, in effect to re-hydrate the body more rapidly by aiding in re-absorption and delivery. It seemed like this article was refuting that as a physiological effect, which I personally find fascinating when related to my own experiences.

Confused newbie with another question: What about calories and cramping? If we fail to take in sufficient calories during a long run, would this also create a situation where cramping could occur? In other words, if we start to run low on fuel would our muscles, etc, and even this mysterious Central Govenor, become more prone to something like cramping? So maybe if salt/electrolytes aren't critical for staving off cramping specifically, failing to maintain a proper balance of these might create a negative spiral ultimately leading to cramping. I'm asking because my biggest issue seems to be getting in "enough" calories as a ramp up time on my feet and I want to avoid/eliminate (as much as possible) something like cramping. Thanks!

I love your articles! As a running coach myself they really offer a lot of info for me to share with my clients. I would love to see you tackle another controversial subject-STRETCHING! Would love to hear your thoughts and see your researach gathering on this one, Thanks!

My experience is mountain biking more than running but I've always been prone to cramp after a few hours of racing. I've found that drinking (flatish) tonic water pre and during racing seems to help. This is another of those 'folk lore' type remedies, but it does seem to help me. Anyone got anything to say about quinine and how that might affect the mechanism described here?

Thanks again KenZ! What's the saying, "we're all an experiment of one". I guess that fits well. Experimentation and time seem to be the only way to get higher-mileage nutrition dialed. I'll be back at it on Sunday! Thanks again!

Could it be that when you exercise hard but not necessarily to the point of cramping and then later, when in bed, you're still experiencing neural fatigue in those muscles and when you put yourself in a position where the muscles are in a shortened position, e.g., you point your toes in bed because, say the bottom of the sheet is tucked in (so your calf muscle is now in a shortened position) your calves then cramp?

That's how I interpreted the following:

"Think of the calf muscle during swimming – your toes are pointed (the ankle is in plantar flexion), which means the muscle is contracting in a shortened position. When the muscle is in this position, then the activity of that Golgi tendon organ is going to reduced even more than normal. Add to this the contraction, which stimulates the muscle spindle, and the net result is that the inhibition of the motor neuron is reduced even further, predisposing one to cramp.

This is why … when you wake up in the middle of the night or sit in a strange position for a really long time, it's when you point your toes that you suddenly go into a fully-fledged cramp!"

To me it sounded like the potential for cramping is enhanced by the position the muscle is in as well as by the neural activity. The question in my mind is what really brings the neural activity back to normal. I have constant calf fasciculations and subsequent cramping and would love to be able to turn that off.

The central governor theory is compelling to a point, but you can still have cramps distal to a nerve block, meaning that the signal never reaches the CNS. But it's fairly nuanced and probably supports the altered neuromuscular control theory. See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC32490…

In conclusion, data from the blocked condition indicate the relevance of peripheral mechanisms in producing a short-lasting involuntary activity after nerve block and results from the intact condition indicate the relevance of afferent inputs in triggering motor neuron hyperactivity.

From the data presented, it can be concluded that the spinal involvement has relevance for the origin of cramps and for their development and that, therefore, peripheral mechanisms are not responsible for cramp origin or development. The reflex mechanisms that influence the threshold may be the same mechanisms that are important in sustaining the cramp: origin and sustenance of cramps are consistent with a positive feedback loop, in which the motor neurons receive afferent inputs resulting in hyperexcitability.

seems to come down firmly firmly on the CNS being the primary source of origin. But how that fits with fatigue induced cramp when the muscles are at rest is a different matter unless as you postulate there is some residual activity in the muscles that somehow gets heightened during sleep

I actually lie on my side/front in bed as a result many years ago of tearing ankle ligaments and breaking bones in one ankle and was unable to bear the weight of bedclothes on that foot so I don't think my calf muscles get stressed during sleep.

Night cramps are not unusual in many folk, athletes or not, but when I do get them it is very severe and effects can last for several hours – hence the interest in them!!

I'm way late to the game to chime in on the discussion, but my cramping history points to another factor that may be affecting my central responses: altitude.

I started out bike racing in 1988 at Washington State U. Most everything I did was at 2000' and below. I remember on our hard days we would go out and just beat mercilessly on each other for hours at a time until only one was left standing. Never had a cramp that I can remember.

From there I moved to Beaverton OR and spent a few years racing on the track at Alpenrose. GOBS of speed and intensity work. No cramps that I can remember from those years.

In 1995 I moved to Colorado. Have done a few seasons of road racing and triathlons since moving here, and have more recently fallen for trail running. I have battled cramps ever since moving to Colorado. Rarely in training, almost always in competition (unless it's just a 45-minute criterium or something). None of the dietary things I've tried in years of experimentation have had any effect.

My experiences clearly fit with the central neuromuscular explanation for cramping. They also point to altitude as a possible input to the stress matrix that is responsible for the onset of cramping … at least in my case.

I started to cramp in this weekends London Ride, a 100 mile road race/ride, it was my hamys that were going around the 80mile mark as the peloton was flying along around 45km on the flats and the hills were done, so I decided to sit in and try to do as little as possible for a while, I also took in some sips of water, which I had put some sea salt and carb solution in, cramps went away after about 10 minutes (I have read Tims book, so have used thirst idea, almost exclusively for my racing). So based on your article, it could have been the reduced effort, or the taste of something salty being picked up by receptors in my mouth, maybe a combination of both.

Why do I hear good results from cyclists and other that Magnesium does help for muscle cramps. Eating a Rennie (Bayer) seems to work during the exercise as the cramp sets on . . . or are we talking placebo again. If not, then chard, spinach, nuts and seeds and fish for example could be beneficial before planning a strenuous workout.

GREAT INFO!! Though, I think jumping to the conclusion that simply Slowing down will make cramps subside is just as dangerous as the original sodium theory.

That said, I am a chronic cramper, and have experimented with all sorts of remedies and I strongly believe cramps are more a result of some sort of fatigue than directly a sodium or electrolyte issue. I also firmly believe and have had better success with sodium by placing directly on the tongue, rather than a coated tablet. Clearly I had better results when I could taste the sodium, so this supports much of your findings. Like JJ, I not only cramp while running but also swimming which seems like you wouldn't fatigue as much. But this is where I think tension and stress MAY play a role. When my calves are fatigued, they will "pulse" with small muscle "twitches" to where it looks like my skin is crawling. I believe this is the electrical firing that the research suggests as well.

REALLY great info here, and can't wait for us to learn more and determine to REAL cause of for us chronic crampers!

The two times I've cramped while running were when I was attempting something new (a long fell race and a Bob Graham Round) and was intimidated by what I'd taken on, so the cramping could be explained by the central governor theory.

However, I also frequently cramp while doing yoga. This happens in my instep while it is not the 'target' of the current yoga posture or movement and is therefore relaxed. Can anyone explain what's going on here?

My feet (arches) will cramp during some yoga postures, pointing toes hard, even during massages when the MT hits some spot. Does weird things to position of my toes. I've had to start pool running in the last week and have had my calves cramp up at certain points (doesn't happen during land runs) – today was first day without. I'm guessing I am stressing the calf differently, in a way it's not used to, and that combined with usual tightness, TP knots & imbalances from my injury are the cause. I try to stretch it out. Yesterday, when both cramped at once after 2hrs, I decided I was done anyway. :) (had stretched out earlier cramp)

Noakes suggests that there is no physiological reason that we need to consume salt during prolonged exercise because we secrete (in sweat) proportionally more water than salt relative to plasma concentrations. It is hard to accept that assertion when we know, from experience, that salt helps. This question has bothered me since I read (most of) his book. Two things have come to my mind regarding the "why" do we need salt question:

1. The water we secrete does not only come from the water we consume. Water is released when we break down food and energy stores (fat, protein, carbohydrates). It is a by-product of metabolism, and we're doing an aweful lot of metabolizing when we run an ultramarathon, particularly of carbohydrates. (When we harvest energy from carbohydrates, we ultimately turn those sugars, glycogen, and other complex carbs into CO2 and WATER.)

2. Unless something is very wrong (hyponatremia or other malfunction), our bodies are very good at regulating blood plasma sodium concentrations in a fairly narrow range that maintains homeostasis (and thus, life). In order to do this, our bodies must sequester and release sodium from somewhere (Noakes also hints at this) to keep concentrations in check, right? (This could be something general in cells throughout the body or in particular tissues… I have no idea.) So, we may not "need" salt in the sense that our blood, muscles, or urine are measurably low in sodium, but we may actually need salt because however our bodies regulate its concentration in bodily fluids, the stores are getting low. Why else would our brain perceive that the intake of salt is making us safer and decide that it is okay to release us from the cramping that is meant to regulate our effort by shutting us down? So, yes, the response is neurological, but there must be a reason our nervous systems responds positively to salt intake when we are cramping, keeping in mind that sodium also happens to be a critical molecule that is required for our nerve cells to talk to each other.

Unlike most folks, salt does absolutely nothing for me. If I'm cramping and take salt, I continue to cramp. In fact it amazes me it affects anyone. Taking in more water or calories also does nothing. Nothing I ingest makes any difference.

The only thing I can do is slow down and/or try to stretch the affected area. Often though it's cramps all over my body so I can't really stretch everything. Just gotta go slower.

The reason I cramp is simply going too hard too long.

The only way for me to prevent cramping is to avoid overdoing it in a race (or in training). E.g., I can't train at intensity x for y hours, and then go train one day (or race) at intensity 2x for 2x hours. The other thing that helps is daily stretching and stretching before (and even during) a race.

Using a heart rate monitor has helped a little with learning to avoid overdoing it. Sometimes in a race I'm too hyped up and will go too hard and the heart rate monitor lets me know to back off.

Thanks for the comment. I agree 100% with your assessment. The only true treatments/prevention strategies for cramping are:

– Sustainable training

– Stride efficiency

– Pacing

For the latter, I'm beginning to feel more and more strongly that heart-rate plays the most important role. Going beyond fat-burning/ventilatory/anaerobic threshold, for prolonged periods, is the primary factor in cramping. It's the brain telling us – via the muscle – that what we're doing is unsustainable.

I'm not sure there's real data to support that, but I'm going to continue to investigate.

This is my most common place to cramp. Inner thigh. On the bike in long triathlons. They are horrible. I'm usually nearly cramping in the hamstrings as well. And both legs go at the exact same time. No stretching position can help because stretching one spot contracts another causing it to cramp more. I generally have to stand absolutely still and attempt to relax (near impossible), or at best do a very very slow walk until things subside.

I don't usually suffer from cramps however around 3 weeks ago I competed in the Waterous Trail on Foot 82Km Ultra in Western Australia. I wanted to do it in under 10hrs and managed to complete in 8:09. I ran faster than I had ever ran an ultra before and I started to get muscle spasms around the 40Km mark. My compression seemed to stop the spasms going into full cramps.

When I reached around 70Km my whole leg, (toes, foot, calf and quads) cramped so badly that I ended up on the ground in agony. I slowly picked myself up and stretched the leg using a nearby tree.

This allowed me to continue my race, although I still felt my leg muscles twitching every time I ran up or down a hill

I Usually notice calf cramps after a marathon. It will delay my return to training for 2-4 weeks. I just recently screwed up my latest marathon by over training. Ran 22 miles at close race pace 4 weeks before. While tapering I noticed cramps at 2 miles. Never did I run again until the morning of the race ……cramps at 3 for one calf and 6 for the other. Just able to get to 13 but all that training down the tubes. I am going to take very much care of my training efforts in the future because now I must rest 6-8 weeks and had a dnf in my race. What a waste. STEPHEN

This information goes against fundamental physiological laws. The blood will be the last thing to show change as it ALWAYS "rights" itself stealing from other tissues…usually muscle. Classic example of this would be gluconeogenesis. This process steals amino acids from muscle to stabilize blood glucose. Magnesium deficiencies result in restless leg yet you won't see blood changes. Adrenal fatigue is finally now recognized as a real disorder yet you'll see nothing in blood tests diagnosing this until it reaches Addison's disease which is a very serious condition.

Joe,there is something I just don't get. I live and train on warm weather,never get any cramps,at all,run as far as 20 miles on my long runs. However,I ran two marathons on cold weather and start cramping around mile 17. I am certain it is not because I am running to fast,because both times was running the marathon slower than how I ran the long runs. When the cramps start,I slow down and try the walk/run strategy,hoewever,cramping gets worse every mile. Thought I have a sodium/potassium deficiency but according to your article,that is not the case,so I am clueless now.

Very interesting conversation. I recently experienced inner thigh cramping after running 9 hours of a 24 hour fixed time race on a flat course. I have run many ultras and attempted or finished four other ultras of 24 hours or more. This time I made a mistake, wearing quad compression sleeves for the first 4 hours of my race. Felt awesome and was way ahead of schedule then got tired of the compression and removed. At about 9 hours, I noticed progressive cramping of my inner thighs that worsened with running but was forced to walk and still had pain. Eventually stopped after 14 hours when I knew I would have to slowly walk it in and would not reach my goal. I had inner thigh swelling the next day and even wonder if I had mild compartment syndrome. Although I have experienced hip flexor pain (and this has improved with S!caps) this is like nothing I have experienced. Any one have any comments on quad compression sleeves and the formation of muscle cramps?

Excellent article (I am an ultra distance cyclist) dealing with one of the thorniest problems in sports performance. A friend called it to my attention.

Since you wrote this there has been another effort to address cramps now called Hot Shots (beta name was Its the Nerve). Website is http://www.teamhotshot.com that was developed specifically to calm nerves down. One nice thing is the product is easily carried so you aren’t reliant in an aid station during an event.